Hydraulic cement and method of cementing in environments having elevated temperatures

ABSTRACT

A mixture of component (1) water-soluble hydroxycarboxylic acid or salt thereof and component (2) boric acid or a water-soluble salt thereof when admixed with an aqueous hydraulic cement slurry increases the normal setting time of the cement slurry. A watersoluble boron containing hydroxy carboxylic acid or salt thereof can be substituted for the above defined mixture.

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United States Patent 1191 Martin 1 Dec. 24, 1974 HYDRAULIC CEMENT AND METHOD OF 2,705,050 3/1955 Davis et a1. 106/90 EMENTIN 1N ENVIRONMENTS HAVING 3,033.23: 3/1325 hibcrthson et a1 artin 6 1 ELEVATED TEMPERATURES 3,234,154 2/1966 Martin 106/90 [75] Inventor: Robert C. Martin, Tulsa, Okla. 3,433,657 3/1969 Pickering.. 106/90 1 3,748,159 7 197 .l [73] Assignee: The Dow Chemical Company, QTSER SSSLCATIONS [06/90 Midland, Mich. Concrete Tech & Practice, W. H. Taylor, 1965, [22] Filed Sept 1972 American Elsevier Pub. Co., p. 185. [21] Appl. No.: 287,458 Primary Examiner-Delbert E. Gantz y! Apphcauon Data Assistant Examiner-James W. Hellwege conmuamnmpa" [38132591 Attorney, Agent, or Firm-Bruce M. Kanuch; William 1971, abandoned, which 13 a continuation-in-part of M Yates Ser. No. 106,560, Jan. 14, 1971, abandoned.

52 11s. 01 106/90, 106/315, 166/294 1 ABSTRACT 51 161.01 C041) 7/02 A mlxwreofpomponent water-soluble h droxy: 158 Field 61 Search 106/90, 314, 315; 166/293, e 11 9; salt thereof an component 294 1563c acitffir a water-soluble salt thereof when admixed with an aqueous hydra.11h;,cement 51nrry ig- [5 References Cited creases the normal settingti'me of the cement slurry. A wa efi'soliifil''mficofitainin h d 0 box lic D T T N 94041. Mxsn y E STA ES PA E TS acid gg saltvthereoi can be slilit l tuted for the above 1,510,795 10/1924 Newberry 106/89 ig mixture 1,852,595 4/1932 Steinour 106/89 2,211,368 8/1940 Dickens 106/315 6 Claims, N0 Drawings Other ingredients which may be present in the slurry include well-known additaments employed in the art, e.g. fluid-loss control agents, of which certain cellulose derivatives, polystyrene sulfonate or polyvinyltoluene sulfonate are illustrative; friction-loss control agents, eg as described in US. Pat. No. 3,254,719 and stabilizers such as an amine derivative of refined lignin, e.g. as taught, for example, in US. Pat. No. 3,234,154 and other known materials.

The ratio of dry hydraulic cement to water is that commonly employed in the known art and may be, for example, between about and about 65 parts by weight (preferably to parts) of water per hundred parts dry weight of cement.

The improved cement is emplaced in a location desired to be cemented, e.g. a geologic formation or wellbore, by employing conventional mixing and pumping equipment and piping layouts. Truck-mounted mixers provided with high velocity pumps are commonly emherein represented. Other cements can he used in the practice of the invention.

EXAMPLE 1 In this series of tests the setting rate of the Class H QLQQBLQUJjQgQHJibggax {as component (2)] or sodiugn gluocoheptonate [as component (1 )1 and various mixtures thereof was determined. Silica flour was used, as is customary in high temperature well cementing, to impart additional strength to the set cement.

The ingredients shown in Table 1 below were admixed in the amounts shown and tested in accordance with API Casing Cementing Section 10, Schedule 1 1, Simulated 20,000 feet and 340 F Circulation Temperature.

The thickening times (API) of the .Class H Cement (containing 35% of finely divided silica flour, of about to mesh) and containing various amounts of borax, a sodium glucoheptonate or both are set forth in ployed. 20 Table 1.

TABLE l Total Retardant API Thickening Time Percent Based on Wt. Ratio By Wt. 66 By Wt. Pan Am. 100 Parts Dry Retardant Borax (1 Consistometcr Cement Borax:(1) (Dry Cement) (Dry Cement) HourstMinutes None 0:52 0.5 Borax 0.5 1:38 1.0 Borax 1.0 1:01 3.0 Borax 3.0 1:29 5.0 Borax 5.0 1:29 0.5 Sodium Glucoheptonate 0.5 0:56 1.0 do. 1.0 2:33 1.5 do. 1.5 4:32 2.0 do. 2.0 6:00 3.0 do. 3.0 6z00 1.0 do. 15 .20 .80 2:30 1.0 do. 1:3 .25 .75 2:04 1.0 do. 1:1 .50 .5 1:47 1.0 do.. 3:1 .75 .25 1:15 1.0 do. 5:1 .8 .2 0:52 1.5 do. 1:5 .25 1.25 4151 1.5 do. 1:4 .30 1.20 5:28 1.5 do. 1:3 .37 1.13 6:12 15 do. 1:2 .50 1.00 6z00 1.5 do. 1:1 .75 .75 6:00 1.5 do. 2:1 1.00 .50 6:OO 1.5 do. 3:1. 1.13 .37 3:31 1.5 do. 4:1 1.20 .30 2:10 1.5 do. 5:1 1.25 .25 3:45 1.5 do. 6:1 1.2 .21 2:15 2.0 do. 1:5 .33 1.67 5:56 2.0 do. 1:3 .50 1.50 6z00 2.0 do. 1:1 1.01) 1.00 6:()0 2.0 do. 3:1 1.50 .50 6:00 2.0 do. 4:1 1.60 .40 6:00 2.0 do. 5:1 1.67 .33 3:25 3.0 do. 1:5 .50 2.50 6100 3.0 do. 1:3 .75 2.25 6:00 3.0 do. 1:1 1.50 1.50 6100 3.0 do. 3:1 2.25 .75 6:O0 3.0 do.. 5:1 2.50 .25 6:00

COMPARATIVE TESTS AND EXAMPLES OF THE INVENTION The data obtained in this Example clearly demonstrates the synergism of a combination of a boric acid or salt thereof and a water-soluble hydroxycarboxylic acid.

In this series of tests Class H Cement (containing 35% by weight of finely divided silica flour) was again used but the testing was conducted at different schedules (taken from APl RP 108 Section 10) as shown in 5 Table 11 which follows.

The thickening times (API) of the Class H Cement containing various amounts of borax and sodium glucoheptonate are shown in Table 11.

1 HYDRAULIC CEMENT AND METHOD OF CEMENTING IN ENVIRONMENTS HAVING ELEVATED TEMPERATES BACKGROUND OF THE INVENTION Aqueous hydraulic cement slurries are frequently used for construction of buildings, surfacing (e.g. roads, parking lots, etc.) and in underground cementing operations, e.g. in geologic formations penetrated by a wellbore (usually employed therein for purposes for securing a casing in place or for water or brine shutoff), and in tunnels, dams, or reservoir constructions.

In many instances the ambient temperature in the cementing environment is sufficiently high to accelerate the normal rate of setting of the cement. In some instances the cement sets up so fast that thereis not sufficient time for the preparation of the slurry and its proper emplacement in the location where it is'to setup.

Various additaments have been added to cement slurries to retard the Late of set thereof.

However, the problem of controlling the setting rate of cement slurries when employed at high temperatures without impairment of the ultimate strength values of the cement has not been fully solved. This problem-is especially acute in oil well cementing jobs performed at ever increasing depths wherein the bottom hole temperature is often so high that conventional cement slurries cannot be employed because they set up in the tubing and annulus before the cementing job can be completed.

Conventional cement slurry compositions comprise, for example, l a hydraulic cement, e.g. Portland, aluminous, pozzolanic, or expansive cements or mixtures thereof (sometimes they also contain gypsum or the like); (2) water; and (3) as desired, additional functional control agents to alter or control certain properties of the cement such as the rate of setting (usually a function of thickening rate). fluid-loss to a porous material (e.g., a loosely consolidated geologic formation) in contact therewith during the setting period, and friction-reducing agents effective during movement through tubes, pipes, casings. and the like.

SUMMARY OF THE INVENTION in environments wherein the normal setting rate of the cement slurry should be retarded. The slurry contains as a required additament, an improved retardant to the rate of setting thereof. The retardant does not have an adverse effect on the ultimate compressive strength of the slurry. The additament is a heretofore unknown combination which is much more effective at the usual troublesome higher temperatures than would be expected from the behavior of each of the components of the combination when used separately. The retardant comprises (l) at least one water-soluble hydroxycarboxylic acid or metal salt thereof and (2) at least one of boric acid or a water-soluble salt thereof. tag. a borate, for example, borax. This combination when added to a cement slurry in an effective amount results in a truly synergistic effect in retarding the setting rate thereof. In place of the above mixture a water soluble boron containing hydroxycarboxylic acid or alkali or alkaline earth metal salt thereof can be employed.

The novel retarded cement can be employed at temperatures as high as between about 200 F and 400 F. Most commonly temperatures between 230 F and about 230 F will be encountered; however. the retardant is effective at higher temperatures if the time existing between mixing and emplacement is not unduly short.

An effective amount of the retardant. is employed to retard the setting rate ofa cement slurry sufficiently to allow its proper emplacement. The amount ofthe retardant. based on I00 parts by weight of dry h draulic cement present can range from between about 0.3 and about 5.0 parts by weight of component (.I) and between about 0.5 and about 5.0 parts by weight of component (2) to make a total of both (I) and (2) of between about l.0 and 10.0 parts based on the I00 parts dry weight of cement present. Preferably between about I and 4.0 parts of each of (l) and (2) are employed. From about 0.1 to l0 parts, preferably 0.1 to about 5.0 parts by weight per I00 parts by weight ofdry cement of the water soluble boron hydroxycarboxylic acid or alkali or alkaline earth metal salt thereof is employed.

Component (2) comprises at least one of boric acid or a water-soluble salt of bomcid. Of the latter natural minerals such as borax, kernite and ulexite are suitable. Other suitabIewafer-soluble salts include, for example, alkali and alkaline earth metal salts, e.g. Li-

rboxyr salt thereof, is any saturated or unsaturated hydroxycarboxylic acid or salt thereof (egaQligflaI- kaline earth metal salt) containing one or more ydroxy groups and one or more carboxylic groups and which is sufficiently soluble in water to be effective as a retarder in the cement slurry. Included by way of example are low molecular weight aliphatic materials such as, for example. tartaric acid, luconic acid, citric acid or salt thereof and higher molecular weight materials such as carboxymethylcellulose glucoheptonic acid or salt thereof and the like. The use of glucohep- .tonic acid or its salt as an additive for retarding the setting of cements is disclosed in US. Pat. No. 3,234,154.

The boron containing hydroxycarboxylic acid or salt thereof is the product formed by reacting a water soluble hydroxycarboxylic acid or salt thereof with, for example, boric acid. It is theorized that this reaction takes place in situ in the cement slurry when components l and (2) are added thereto. Tests of preformed boron containing hydroxycarboxylic acid or salt thereof as a retarder tend to support this theory since such boron salts also are found to synergistically retard the set of cement slurries. especially under elevated temperatures. Suitable boron containing compounds include. for example, those formed by the reaction ofa hydroxycarboxylic acid or salt thereof and boric acid. Included by-way of example are 5' n te. calcium borogluconate. sodium borotartate. and the 300F l8.000 ft.

248F I6.000 ft.

AP! Thickening Time Hours and Minutes. APl Schedule 206F l4.000 ft.

4z00 4z00 4200 4z00 4z00 4:00 4200 4:00 4:0O 4:0O =0 TABLE ll l72F 12.000 ft.

1:40 3:34 4:54 lz40 4z00 4 00 4 00 4 00 4 00 Percent Retardant Retardant Based on I00 Parts Wt. Ratio Cement by Dry Weight Borax (l) 1 131134 36330 4 OOOOOOOOOOOlLll.

380F 20.000 ft.

conducted over a period of 24 hours at 3.000 p.s.i. autoclave pressure in accordance with the API Schedules shown in Table ill to show the effect of the presence of 25 the retardant according to the invention. on compressive strength values of the set cement.

TABLE III Compressive Strength (psi) 260F 290F 320F 12.000 ft. 14,000 a. 16.000 0.

Retardant Wt. Ratio Borax:( l

Those tests wherein the slurry did not set within the time shown. subsequently set when the temperature was higher as shown in Table Ill. inlru.

[t can be seen by examination of Table II that any ratio of from 3 to l borax to l to 3 of sodium glucoheptonate gave desirable setting rates under the conditions of the four schedules tested and that the length of time of the setting was greatly increased by increasing the fimwtmuv l l .l

Sa -97 7 TJMWMMU ll!!! 005000 020 fi M c e e e e n n n n H 1 .31 34 .123 .3 3 3 .3 .2 680414 N00000N000000N0 000N N 22 EXAMPLE 2 total parts of the retardant to the dry cement weight.

Class H Cement (as described in Example I) was again employed in this series of tests. This series was 'EXAMPLE 3 Thickening time tests were conducted on a Class H cement obtained from Oklahoma Cement Company. A

The compressive strength of samples of the same cement slurry containing various amounts of sodium boroglucoheptonate were also determined. The results of these tests are set forth in the following Table V.

TABLE V Percent Rctarder Compressive Strength. psi Based on API Schedule Test Weight of 95 105 1 18 No. Retarder Dry Cement 320F 350T DUFF 1 Sodium Boroglucoheptonate None 4812 31 71 $147 2 do. 0.3 1718 3 do. 0.4 1613 4 do. 1.3 1462 5 d0. 1.4 1 1X6 6 do. 1.1 M32 7 do. 1.2 6205 cement slurry was formed containing 800 grams ce- EXAMPLE 4 ment, 280 grams silica flour, and 448 grams water. To various samples of the cement slurry were added various amounts of sodium boroglucoheptonate or a mixtureofi 3 pa r ts byaveight of borax and 1 ar TwdTtTm glucgg tgnate and 1 part silica flour. The thickening 25 time of the various mixes was determined by API schedules 9, l0 and l 1. The results of the tests are set forth in the following Table IV.

TABLE IV Several compounds or mixtures of various compounds were tested to determine their effect on the thickening time of Class H cement slurry containing 800 grams of Class H cement, 280 grams silica flour and 448 grams of H 0. The tests were run according to API PB 10 B Schedule 1 l. The results ofthese tests are set forth in the following Table VI.

Percent Retarder Based On 9 10 I 1 Test Weight of 248F 300F 340F No. Retarder Dry Cement 16,000 ft. 18,000 ft. 20.000 ft.

1 Sodium Boroglucoheptonate 0.3 2:00 2 do. 0.4 +8100 3 dov 0.9 +8100 2:11 2:54 4 do. 1.0 +8:00 3:06 3213 5 do. 1.| +8z00 4:39 5:20 6 d0. 1.2 +8100 2:30 +8:00 7 do. 1.3 +l'l:00 5:24 +8:00 8 do. 1.4 +8:00 +8;00 +8z00 9 3 Parts Borax. 1 Part 1.3 2:42

Sodium Glucoheptonate. 1 Part Silica Flour 10 do. 1.5 5:20 1 1 do 1.7 +8z00 12 do. 1.9 +8:00

TABLE V1 Percent Retarder Retarder Parts by Based on Thickening Test Weight of Weight 01' Time No. Each Dry Cement HrszMins l 3K,B O :l SGH" 1.5 +l0:00 2 3 Borax: 1 SGH 1.0 2:48 3 3K,B,O;:1 SGH 1.0 6:00 4 3.6 Borax:l SGH" 1.15 6:00 5 Quebracho Tree 2.0 3:20

Bark Extract 6 Hemlock Tree 3.00 2:10

Bark Extract 7 3 Borax l Ouebracho 3.00 6:00

Bark Extract 8 3 Borax I Ouebracho 2.00 5:00

Bark Extract 9 3LiB.O,:l SGH 1.00 5:00 10 3 Borax:l Tartaric Acid 1.5 6:00 11 -S Borax:l Tartaric Acid 1.5 1:49 12 Borax:5 Tartaric Acid 1.5 5:51 13 1 Borax:3 Tartaric Acid 1.5 8:00 14 3 Borax:l Delta-Gluconolactone 1.5 6:00 15 3 Borax:1 Delta-Gluconolactone 1 4:16

'SGH is sodium glucnheptonat What is claimed is:

1. [n the method of em placing an aqueous hydraulic-- cement slurry into an environment having an elevated temperature of at least about 200 F which temperature would normally cause a premature setting of the hydraulic cement, the improvement which comprises:

admixing with said hydraulic cement slurry a water soluble alkali or alkaline earth metal salt of a boron containing hydroxycarboxylic acid in an amount ranging from about 0.1 to about 10 parts by weight per 100 parts by weight of dry cement to retard the setting rate of said hydraulic cement slurry at said elevated temperature. 2. The method of claim 1 wherein the salt of the water soluble boron containing hydroxycarboxylic acid is an alkali metal salt.

3. The method of claim' 1 wherein the salt of the water soluble boron containing hydroxycarboxylic acid is an alkaline earth metal salt.

4. A hydraulic cement composition comprising: a. a hydraulic cement slurry, and

b. about 0.1 to about 10 parts by weight of an alkali water soluble boron containing hydroxycarboxylic acid is an alkali metal salt.

6. The composition of claim 4 wherein the salt of the water soluble boron containing hydroxycarboxylic acid is an alkaline earth metal salt.

f0? M C 7 6 "H050 UNITED STATES PATENT OFFICE (5/69) CERTIFICATE OF CORRECTION 3,856,541 December 24, 1974 Patent No. Dated Inventor) Robert C. Martin It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 9, delete "230" and insert -340--.

Column 5, Table II, column 1, line 1, delete "Percent Retardant" and insert --Total Retardant Percent-.

Column 8, Table VI, column 2, item 12, delete "Borax:5 'Iartaric Acid" and insert --1 BoraxzS Tartaric Acid--.

Signed and sealed this 22nd day of April 1975; v

(SEAL) V Attest: C. MARSHALL DANN RUTH C. MASON Commissioner of- Patents Attesting Officer and Trademarks H050 UNITED STATES PATENT OFFICE 569 CERTIFICATE OF CORRECTION Patent R 3,356,541 Dated December 24 1974 Inventor(g) Robert C Martin It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 9, delete "230" and insert --34o--.

Column 5, Table II, column 1, line 1, delete 'Percent Retardant" and insert -Total Retardant Percent-.

Column 8, Table VI, column 2, item 12, delete "Borax:5 Tartaric Acid" and insert ---1 Borax=5 Tartaric Acid-. I

Signed and sealed this 22nd day of April 1975.

(SEAL) Attest C. MARSHALL DANN RUTH C. MASON Commissioner of- Patents Attesting Officer and Trademarks 

1. IN THE METHOD OF EMPLACING AN AQUEOUS HYDRAULIC CEMENT SLURRY INTO AN ENVIRONMENT HAVING AN ELEVATED TEMPERATURE OF AT LEAST ABOUT 200*F WHICH TEMPERATURE WOULD NORMALLY CAUSE A PREMATURE SETTING OF THE HYDRAULIC CEMENT, THE IMPROVEMENT WHICH COMPRISES: ADMIXING WITH SAID HYDRAULIC CEMENT SLURRY A WATER SOLUBLE ALKALI OR ALKALINE EARTH METAL SALT OF A BORON CONTAINING HYDROXYCARBOXYLIC ACID IN AN AMOUNT RANGING FROM ABOUT 0.1 TO ABOUT 10 PARTS BY WEIGHT PER 100 PARTS BY WEIGHT OF DRY CEMENT TO RETARD THE SETTING RATE OF SAID HYDRAULIC CEMENT SLURRY AT SAID ELEVATED TEMPERATURE.
 2. The method of claim 1 wherein the salt of the water soluble boron containing hydroxycarboxylic acid is an alkali metal salt.
 3. The method of claim 1 wherein the salt of the water soluble boron containing hydroxycarboxylic acid is an alkaline earth metal salt.
 4. A hydraulic cement composition comprising: a. a hydraulic cement slurry, and b. about 0.1 to about 10 parts by weight of an alkali or alkaline earth metal salt of a boron containing hydroxycarboxylic acid per 100 parts by weight of dry cement to retard the setting rate of the hydraulic cement slurry when emplaced in an environment having an elevated temperature of at least about 200* F.
 5. The composition of claim 4 wherein the salt of the water soluble boron containing hydroxycarboxylic acid is an alkali metal salt.
 6. The composition of claim 4 wherein the salt of the water soluble boron containing hydroxycarboxylic acid is an alkaline earth metal salt. 